There are various types of visual display systems allowing a synthetic image to be superimposed on an outside environment. One possible solution, which is shown in FIG. 1, involves implementing a stereoscopic image projector. The visual display system 10 then comprises:                a projector 11 for stereoscopic images referred to as “3D” images that is capable of generating at least two images called “Right Eye”/“Left Eye” that represent one and the same object. In the case of FIG. 1, the object is a sphere S;        a diffusing semitransparent screen 12 onto which the “Right Eye”/“Left Eye” images are projected;        a pair of spectacles 13 having means for separating the “Right Eye”/“Left Eye” images and first detection means 14 and intended to be worn by a user;        second detection means 15 linked to a fixed reference frame R, and, in association with the first detection means 14, allowing detection of the spatial position of the pair of spectacles 13 in this fixed reference frame;        an electronic computer 16 comprising at least the following functions:                    acquisition of the signals from the detection means 14 and/or 15 and computation of the position of the pair of spectacles;            computation of the position of the stereoscopic image corresponding to the position of the pair of spectacles;            computation of the two Right Eye/Left Eye images.                        